Re: Why are tables sizes so big? - Mailing list pgsql-general

From Tom Lane
Subject Re: Why are tables sizes so big?
Date
Msg-id 9480.983979766@sss.pgh.pa.us
Whole thread Raw
In response to Re: Why are tables sizes so big?  (Richard Huxton <dev@archonet.com>)
List pgsql-general
Richard Huxton <dev@archonet.com> writes:
>> The CSV file has 5 text fields that I change to char size 10, float, float,
>> int and float. That in it's self sould make the data on the server much
>> smaller, but it is not, it is bigger, why?

> char  = 10 + 4
> floats= 8 * 3
> int   = 4
> oid   = 4

> That's at least 46 bytes per row plus indexes - which can take up a lot.

Actually, the per-row overhead is not just an OID: there are several
other system fields too.  On a typical machine it's going to be 32 bytes
not four.  Possibly more if you have nulls in the row; see
src/include/access/htup.h if you're interested.

            regards, tom lane

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